Improvement in platform-scales



T. FAIRBANKS.

Platform Scale.

No. 26,485. Patented Dec. 20, 1859.

nv iETERs. holmuthogmpher. Washington. 0. c.

UNTTED STATES ATENT Trice.

IMPROVEMENT lN PLATFORM-SCALES.

Specification forming part of Letters Patent No. 26,185, dated December 20, 1859.

To all whom it may concern.-

Be it known that I, THADDEUS FAIRBANKS, of St. Johnsbury, in the county of Caledonia and State of Vermont, have invented a new and useful Improvement in Platform-Scales for IVeighing Heavy Bodies; and I do hereby declare that the same is fully described and represented in the following specification and the accompanying drawings, of which- Figure l exhibits a ground plan of a platform-scale provided with my invention, the upper planking of the platform not being shown in such drawings. Fig. 2 is a longitudinal. sectional view showing the long multiplying-levers. Fig. 3 is a transverse vertical and central section, while Fig. a represents an end view, and Fig. 5 a side elevation, of the platform. Fig. (3 is a side view of the hanging or stirrup link and its rocker-block, to be hereinafter described. Fig. 7 is a transverse section of the two; Fig. 8, an edge view of them, the last three figures being drawn 011 a scale enlarged relatively to that of the others.

The nature of my invention consists, first, in supporting the fulcrum of the transmittinglever by the platform or an extension therefrom; also, in the combination'of a rockerblock with a stirrup-link and the bearingpins of the multiplying and transmitting levers; also, in constructing the platform with passages through its end timbers, such being for the reception of the inferior arms of the multiplying-levers and to aid in reducing the depth of the pit required for the scale; also, in providing such platform with loop passages leading downward from the said lever-arm passages, as hereinafter described, such, also, contributing to a reduction of the depth of the pit.

In the drawings, A represents the weighingplatform, and 13 its surrounding or pit frame, such platform being supported by means of multiplying-levers O 0, depending from the frame B, as shown in Figs. 1, 2, and a. The inferior arms of the 1nultiplying-levers pass through passages o a made through the end timbers 71% of the platform-frame, such passages being furnished with vertical passages c 0", leading out of them, respectively, and through the end timbers. Each of these latter passages is for the reception of the suspensiou-link d, by which the platform is hung to the arm of the inultiplying-lever. The inner ends of the said multiplying-levers are suspended from a transmitting-lever D, whose knife-edge bearing, or pins (4 receive the two stirrup-links Z) l) for sustaining the inner ends of the inner arms of the two levers C 0. Each of the said stirrup-links, instead of resting di rectly upon its knife-edge bearing a, is sup ported upon a rocker-block (I, that rests upon the said knife-edge bearing, and has its un der surface formed with a curved groove, as shown at 6, running transversely with respect to the upper part of the stirrup-link or that which bears upon the block, the groove being curved both longitudinally and transversely. The upper part of the said bearingblock is constructed with an angular recess 72, suitably formed to receive the angular bearing i of the cross-ba 7c of the stirrup-link, the whole being as shown in the drawings. The transmitting-lever D serves, in connection with another lever E, (supported by the frame 15, as shown in Fig. 3,) to transmit to the suspensiona'od Z of the steelyard or weighingdever the power or pressure of the 1nultiplying-levers O O.

The fulcrum of the lever D is supported directly from the platform A or an extension therefrom, as shown at m in Fig. In other words, the knife-edge bearings of the said lever D rest in ring-bolts projecting from the said platform A.

The advantages obtained by supporting the transmitting-lever from the platform, instead of sustainin its fulcrum or fulcra by a standard or other equivalent devices projecting upward from the bottom of the pit in which the platform may be placed, are that by such I am enabled to obtain a very shallow and portable platform-scale and to dispense with the pit-supporting devices of the trans1nittin lever, whereby, generally or comparatively speaking, I can employ a pit of less depth. Furthermore, by means of the rocker-bearing of each stirrup-link, the knifeedge bearings of the lever O and that of the stirrup-link are caused to adjust themselves in a vertical line or plane with one another under any movement of the lever, as the rocker-block, in consequence of its rocker or curved form, will enable the upper part of the stirrup-link to swing into such line or plane passing through the knife-edge bearings of the inner ends of the lever 0.

Having thus described my invention, what I claim is 1. Supporting the fulcrum of a transmitting-lever D by the platform or an extension therefrom, essentially as specified.

2. The combination of the rocker-block with the stirrup-link and the bearing-pins or knife- I edges of the connected levers G D, substantially as described. 

